Asteroid Defense

Asteroids are coming!
Protect the planets in your care by rotating the planetary shields to intercept any incoming red-glowing asteroids.
After the asteroids hit the shields, they can be mined for power-ups. Rotate the planets again to allow space stations to capture green-glowing asteroids with tractor beams and use them to upgrade your defenses or increase your score.
Keep the red-glowing asteroids away from planets and the green-glowing ones close to space stations.